The TF silicon baseline
PVcomB uses an industry-oriented processing line for thin-film silicon solar modules of 30 x 30 cm² substrate size. All relevant process steps from cleaning the glass-substrate through TCO and silicon deposition, series interconntection up to the contacting and encapsulation have been established and are continuously being further developed at PVcomB.
Since our main focus is on industry-oriented processes and challenges a stable and highly-reproducible "baseline process" has been established as a benchmark. Reference modules with state-of-the-art performance are prepared periodically enable evaluation of new materials, processes and equipment with respect to module properties. In this way, new processes are quickly and reliably transferred and upscaled to industrial manufacturing lines. An overview poster of our a-Si/µc-Si baseline was presented at the 27. EUPVSEC in Frankfurt/Main, 2012.
The comprehensive range of measurement and testing instrumentation at PVcomB is matched to the special needs of a-Si/µc-Si technology and the requirements of developing 30 x 30 cm² thin-film solar modules.
Fig. 1: Schematic description of the a-Si/µc-Si baseline process at PVcomB on 30 x 30 cm². Comprehensive analytics of processes, layers and devices are integrated along the whole production line.
Main components of the silicon baseline
The heart of the silicon baseline is a plasma-enhanced chemical vapor deposition (PECVD) system to deposit the silicon layers. This industrial cluster tool (AKT 1600A) allows the deposition of silicon-based layers in three process chambers. The tool is fully automated and equipped with in-situ diagnostics such as residual gas analyzer (RGA), optical emission spectroscopy (OES) and self excited electron resonance spectroscopy (SEERS).
An in-house data management system has been developed to provide easy access to process and measurement data. All processes (deposition of amorphous and microcrystallin silicon (a-Si:H und µc-Si:H) and alloys as well as NF3 cleaning processes) are monitored in terms of materials quality, deposition rate, gas utilization and layer homogeneities and are continuously being further optimized.
Beyond this, the methodology at PVcomB is adapted and further know-how is created, to also monitor and optimize these processes in industrial module manufacturing using comparable methods.
- Development of new PECVD processes and in-situ analytics
- Development of innovative materials, solar cells and module concepts
- Evaluation and benchmarking of new materials and processes
- Development and testing of new measurement technologies and methods
- Consulting in process development and R&D strategies ("road maps")
- Preparation of solar module prototypes
- Deposition of thin layers on 30 x 30 cm2 substrate size
Collaborations and research projects
In frame of our thin-film Si activities we are collaborating with several partners from industry and research institutes.
Both public funded projects and bilateral alliances are used to push the a-Si/µc-Si technology and develop future solar module concepts based on thin-film silicon.
Record results of a-Si:H/µc-Si:H tandem solar cell devices at PVcomB
Fig. 2: Solar cell test structures (1 cm²), minimodule (10 x 10 cm²) and 30 x 30 cm² module of a-Si:H/µc-Si:H tandem solar cells on glass.